I will study the surface membrane of cultured rat Schwann cells and peripheral nervous system (PNS) myelin in relation to the phenomena of myelination and demyelination. Monoclonal antibodies to the Schwann cell surface and PNS myelin membrane constituents will be generated and used as immunological probes to identify and characterize the major molecular components of these two membranes through immunochemical techniques. These antibodies will be used as surface markers for identification of Schwann cells and their possible subpopulations in culture and for study of their cell lineage. The function of the target cell surface antigens in the process of normal myelination will be studied in vivo by injecting the specific hybridoma clones and their antibodies into the pregnant mice at different stages of gestation to look for evidence of arrest of myelination in the newborns exposed to the maternal antibodies in utero. Neurophysiological and neuropathological methods will be used to study abnormalities of myelin and Schwan cells. The possible demyelinative effect of these antibodies to the different surface antigens will be tested in vivo by injection of clones and/or antibodies into normal adult mice. The in vitro effect of these antibodies on myelinated or myelinating PNS cultures will also be observed. The techniques developed during the course of this project should, in the long-term, be directly applicable to Schwann cells and myelin from human peripheral nervous system.